1. Field of Invention
This invention relates to a compression and shear-producing tool, specifically to one which allows application of firm but gentle pressure for the purpose of shelling nuts.
2. Prior Art
The primary function of a nutcracker is to crack the shells of nuts so that one can extract the nutmeats cleanly and efficiently. A secondary purpose is to provide a functional toy or gadget which can entertain, amuse, or stimulate both adults and children.
Heretofore, hand-held nutcrackers have generally comprised two levers joined at one end. When squeezed between jaws set roughly parallel to these levers, the nut's shell would suddenly shatter, scattering fragments of the meat and shell.
In attempts to better modulate this action through improvement of mechanical advantage, nutcrackers have been invented having curved jaws set at angles to the levers. These attempts are exemplified in U.S. Pat. Nos. 343,351 to Watrous, June 8, 1886, and 4,425,707 to Polsfuss, Jan. 17, 1984. Unfortunately, the particular shapes chosen for these jaws, and the locations of the pivot points in respect to the jaws, ensures that for them to function as intended on a wide range of nuts, they would have to be constructed on an absurdly large scale.
At least one large-scale commercial nut husker has been invented which improves upon these two designs by turning one of the two curved surfaces upon its own circular axis: U.S. Pat. No. 4,819,331 to Joyama, Apr. 11, 1989, presents a commercial nut-husker comprising an internal rotor and an external stator having circular and semi-circular cross-sections respectively, and each having a plurality of cracking projections on their opposing surfaces. The stator is positioned so as to provide a decreasing gap between itself and the rotor, so that the circular rotor, turning on its axis, forces nuts of various sizes into the ever-narrower gap until they crack. However, the choice of two circular curved elements restricts the range of sizes of acceptable nuts to an unacceptable degree when the device is scaled-down to be hand-held.
There are many other types of nutcrackers on the market, combining in various ratios: inadequate precision, inadequate force, awkwardness, excessive size, excessive complexity, excessive operation time, and excessive production costs. Some nutcrackers employ screw-threads for exerting steady pressure, but these require additional time to be adjusted to fit each nut. Moreover, they must be reset for each nut even when cracking nuts of the same size. Jack-type nutcrackers also require adjustment and are also unnecessarily complicated.